species discussion: T. derasa

[hobogato]

reference thread for those thinking about housing this species.

please post anything and everything about your experience with derasa clams. some things you might include:

pics
how big was it when you got it?
how long have you had it?
what are the specifics for its care in your tank (lighting, flow, placement in tank, special feeding, etc)?
problems to look out for
anything else you can think of

[Reefer4ever]

I had this clam for 3 days before it mysteriously died. It was 5 inches away from two T5HO bulbs. It was 3 inches long and there was a gentle flow around the clam. Here is a picture the day I got it:

http://i847.photobucket.com/albums/ab37/reefer4ever/66gallon001.jpg

Here is the same clam 3 days later... dead(or at least very close to it):

http://i847.photobucket.com/albums/ab37/reefer4ever/dyingclam002.jpg

[Reefer4ever]

I do not think the clam died from too little light because I do not think it would die this fast with out enough light.

[tebstan]

Probably not light, since derasas require low light compared to maxima and crocea. You say its 5" away from bulbs, but in both pics its on the sand bed. If you were moving it frequently, that could stress it. What lights was it under before? could also be light shock. What else is in the tank with it?

With most corals you can assume there is always hope, and wait until there is a bare skeleton before giving up. Unfortunately, not so with clams. Once they begin a rapid decline it is virtually impossible to bring them back.

Does your derasa show any signs of life? Can is close it's own shell? If that muscle is deteriorated, it is as good as dead, and you might as well take it out of the tank. If it still can move, and you're willing to fight for it's life, check out this book:
http://www.amazon.com/Giant-Clams-Aquarium-James-Fatherree/dp/0978619404/ref=sr_1_1?ie=UTF8&s=books&qid=1286333793&sr=8-1-spell

[Reefer4ever]

When I had it, it only had a blue/green chromis in it. It was a very shallow tank. I may have been exaggerating a bit. It was about 9 inches away from the light and the tank is about 7 inches tall. It came from Alamo Aquatics and Exotics. That is just down the road from Gabe's shop and has a big yellow sign that says "Pet Shop" if you do not know where that is. It came from metal halides on a bare bottom tank about 30 inches from the light(I do not know the watts).

[jrsatx20]

which tank is this in now

[Reefer4ever]

This was in my 8 gallon tank.

[Big_Pun]

what where parameters in tank, clams need a very stable system. and small tanks are very hard to stablize, things go bad fast. i have a 3g pico with sps and had to do overkill with my filtration and do water changes every 3 days or sooner and still struggle with keeping it stable.

[Reefer4ever]

All of my parameters were good for the time I had the clam and the tank was about 6 months old. NH3/NH4, NO3, NO4, and PO4 were all 0 except NO4 which was about 5. Ca was 460 at the time.

[ErikH]

My derasa's shell split in two. I tried everything to keep it together using a rock on each side, but it would just flip flop side to side. It eventually died.

[Reefer4ever]

You mean at the bottom where they attach? How did that happen? You have any pictures?

[ErikH]

No idea how it happened, the clam was over a year old. I just noticed one day it was slumped over.

[Reefer4ever]

Did you have any big fish or crab that could have ripped at the base or hit the shell hard enough to break the seal on the bottom of the clam? That is very odd.

[CoryDude]

Clams are also susceptible to poor shipping. With all the things involved in the collection, holding, distribution, shipping, etc, it could have been overstressed and on it's way out before you even bought it.

I had a deresa clam who's shell grow to over 12". When the mantle was extended it, would take up over a 1/3 of the bottom of a 90 gallon tank. It develops a very pretty brown/blue/green spotted pattern along the edges of it's mantle. It was also the most tolerant of all the clams I've had experience with. Very good clam for a beginning aquarist. Here's a pic of mine about 2 years before it died:

http://i401.photobucket.com/albums/pp100/cpryor74/TankShots/CIMG0478.jpg

[hobogato]

dylan, a couple of possibilities:

1. trapped air - if the clam was exposed to air and not burped when returned to water, an air bubble could have been trapped inside. this can cause any tridacnid clam to close up and die.

2. parasitic protozoan - Perkinsus olseni was a very common infection causing lots of clam deaths recently, especially in wild collected T. derasa clams from Vietnam.

another possibility is a parasitic flatworm - had one take out a few clams several years ago.

[hobogato]

that is a nice clam cory, i bet it was a real calcium hog!